Graphitic C₃ N₄ Decorated with CoP Co-catalyst: Enhanced and Stable Photocatalytic H₂ Evolution Activity from Water...

In this work, graphitic C₃ N₄ decorated with a CoP co-catalyst (g-C₃ N₄ /CoP) is reported for photocatalytic H₂ evolution reaction based on two-step hydrothermal and phosphidation method. The structure of g-C₃ N₄ /CoP is well confirmed by XRD, FTIR, TEM, XPS, and UV/Vis diffuse reflection spectra techniques. When the weight percentage of CoP loading is 3.4 wt % (g-C₃ N₄ /CoP-3.4 %), the highest H₂ evolution amount of 8.4×10²  μmol g^-1 is obtained, which is 1.1×10³  times than that over pure g-C₃ N₄ . This value also is comparable with that of g-C₃ N₄ loaded by the same amount of Pt. In cycling experiments, g-C₃ N₄ /CoP-3.4 % shows a stable photocatalytic activity. In addition, g-C₃ N₄ /CoP-3.4 % is an efficient photocatalyst for H₂ evolution under irradiation with natural solar light. Based on comparative photoluminescence emission spectra, photoelectrochemical I-t curves, EIS Nyquist plots, and polarization curves between g-C₃ N₄ /CoP-3.4 % and pure g-C₃ N₄ , it is concluded that the presence of the CoP co-catalyst accelerates the separation and transfer of photogenerated electrons of g-C₃ N₄ , thus resulting in improved photocatalytic activity in the H₂ evolution reaction.